Support deadline · MuleSoft
Mule 3 end of support: your options and timeline
Mule 3.9 extended support ended on 20 March 2024: 928 days ago (MuleSoft versioning and back-support policy, checked on 2026-10-03).
A Mule 3 to Mule 4 migration is no longer optional for supported production use: standard support for Mule 3.9 ended in March 2021 and extended support in March 2024, and MuleSoft stops applications running on end-of-life runtimes on CloudHub (MuleSoft versioning and back-support policy, checked on 2026-10-03). The Mule Migration Assistant helps, but MuleSoft says it "does not deliver a fully functional app" (MuleSoft docs: migrating to Mule 4, checked on 2026-10-03).
Last updated . Figures are re-checked quarterly.
The Mule 3 timeline
| Date | What happens | Source |
|---|---|---|
| 20 March 2021 | Mule 3.9 standard support ends. | (MuleSoft versioning and back-support policy, checked on 2026-10-03) |
| 20 March 2024 | Mule 3.9 extended support ends. | (MuleSoft versioning and back-support policy, checked on 2026-10-03) |
| After extended support | Applications on end-of-life runtimes on CloudHub are stopped; Hybrid Standalone and Runtime Fabric get limited end-of-life assistance without patches. | (MuleSoft versioning and back-support policy, checked on 2026-10-03) |
| 6 August 2027 | Mule 4.9 LTS standard support ends (extended support to 6 February 2028), a date to plan your target version around. | (MuleSoft versioning and back-support policy, checked on 2026-10-03) |
What end of life means in practice
MuleSoft's back-support policy states: "Applications running on End of Life runtimes on CloudHub will be stopped when Standard and Extended Support end." (MuleSoft versioning and back-support policy, checked on 2026-10-03) On customer-hosted runtimes the applications keep running, but without patches, which matters for security reviews and audits. The policy page on mulesoft.com now redirects to a PDF hosted by Salesforce.
The gap between "still running" and "supported" is where most Mule 3 estates sit today. Nothing fails on the day support ends; the cost shows up later, as an unpatched vulnerability, a connector that no longer works with an upgraded endpoint, or an audit finding that forces a rushed migration. Planning the move on your own schedule is cheaper than doing it under one of those triggers.
Your options
- Migrate to Mule 4 by hand. MuleSoft offers a fully manual process, or a partially automated one (MuleSoft docs: migrating to Mule 4, checked on 2026-10-03).
- Use the Mule Migration Assistant (MMA). It migrates project structure, generates descriptors such as pom.xml and mule-artifact.json, and adapts much of the code, but "some additional steps are required" (MuleSoft docs: migrating to Mule 4, checked on 2026-10-03). It does not support incremental migration, complex MEL and DataWeave may need manual work, and DataMapper must first go through the DataWeave Migration tool. MMA is offered under Community connector terms, not as a fully supported product.
- Target a current LTS runtime. Mule 4.9 LTS has standard support to 6 August 2027; Mule 4.6 LTS standard support ended on 6 August 2026 (MuleSoft versioning and back-support policy, checked on 2026-10-03).
- Re-platform instead. If a Mule 3 estate needs rewriting anyway, it is a natural point to compare MuleSoft alternatives on cost and effort.
Migration-readiness checklist
- List every Mule 3 application with runtime version, deployment target and business owner.
- Flag MEL-heavy flows, DataMapper usage and custom Java components.
- Record which connectors each app uses and whether a Mule 4 version exists.
- Run MMA on a representative app and measure the manual work it leaves.
- Plan to a supported Mule 4 LTS date, not just to "off Mule 3".
Disclosure: iPaaS Tools offers migration tooling and services, so we have an interest in this topic. We have no affiliation with, and are not endorsed by, any vendor named here; product names belong to their owners.